1. Field of the Invention
This invention relates, generally, to bailers. More particularly, it relates to a bailer having a valve assembly at its lower end that seals effectively against leakage when seated.
2. Description of the Prior Art
Bailers are elongate cylindrical tubes that are lowered into containers for liquid fluids, bodies of water, and the like for the purpose of taking a sample of the liquid fluid so that laboratory tests can be performed thereon.
In the industry standard bailer, a free-floating ball valve at the lower end of the bailer unseats from its valve seat when the bailer is lowered into a liquid fluid, i.e., as liquid fluid flows upwardly into the hollow interior of the bailer. The ball valve travels downwardly into seating relation to its valve seat when the bailer is lifted upwardly from the liquid fluid. When properly seated, the ball valve should substantially prevent leakage of the liquid fluid from the hollow interior of the bailer.
In practice, however, the ball valve leaks profusely. The clothing of the person carrying the bailer to a vehicle that will transport the collected sample to a lab often gets wet as the liquid fluid within the bailer leaks part the ball valve. If the liquid fluid is an acid or other irritant, the leakage is more than a mere nuisance. Even if the liquid fluid is just water, the loss of sample is undesirable.
The seat for the ball valve is an annular step formed on an interior surface of a frusto-conical wall that defines the lowermost end of the bailer. A single grain of sand on the annular step can defeat proper seating of the ball valve. Sand and other particles are commonly found in the liquid fluids that are collected by bailers in the field.
What is needed, then, is an improved valve assembly at the lowermost end of a bailer. The improved valve would not be defeated by a single grain of sand and would not be rendered ineffective by even relatively large amounts of sand.
However, it was not obvious to those of ordinary skill in this art how a leak-inhibiting valve assembly could be provided, in view of the art considered as a whole at the time the present invention was made.
The long-standing but heretofore unfulfilled need for an innovation that overcomes the limitations of the prior art is now met by a new, useful, and non-obvious invention. The present invention includes a substantially leak-free valve assembly for admitting liquid fluid into the hollow interior of a bailer as the bailer is lowered into a liquid fluid and for retaining liquid fluid within the hollow interior when the bailer is lifted from the liquid fluid.
A support means in the form of a spider member spans a hollow interior of the bailer near its lowermost end. A central bore is formed in the spider and has an axis of symmetry that is substantially coincident with a longitudinal axis of symmetry of the bailer.
The bailer is of the type that has a cylindrical main body, frusto-conical sidewalls at the lowermost end of the main body, and a cylindrical downs pout at the lowermost end of the frusto-conical sidewalls.
A hemispherical-in-configuration valve body is secured to a lowermost end of a straight valve stem. The valve stem is slideably received within the central bore formed in the spider so that the hemispherical valve body rises and falls as liquid fluid flows into and out of the hollow interior of the bailer, respectively. The valve stem and the central bore cooperate to maintain the hemispherical valve body in substantial coincidence with the longitudinal axis of symmetry of the bailer as the hemispherical valve body rises and falls.
An annular concavity is formed in an interior surface of the frusto-conical sidewalls. It is configured to substantially match an exterior surface of the hemispherical valve body so that substantially no leakage of liquid fluid from the hollow interior of the bailer occurs when the hemispherical valve body is seated against the annular concavity.
In a variation of the first embodiment, an annular ridge of predetermined height is formed on the interior surface of the frusto-conical sidewalls. The annular ridge is integrally formed with the annular concavity and is adapted to provide a barrier to passage to at least one grain of particulate matter so that the at least one grain of particulate matter does not interfere with seating of the hemispherical valve body against the annular concavity.
In a second embodiment, the valve body and its matching valve seat are frusto-conical in configuration, and a variation of the second embodiment includes the particle barrier of the first embodiment.
In a third embodiment, the valve body and its matching valve seat are downwardly tapered to form an elongate, narrow slot. A variation of the third embodiment includes a particle barrier formed in the downwardly-tapered sidewalls of the valve seat.
It is a primary object of this invention to advance the art of bailers by providing a bailer that is substantially leak-free.
A more specific object is to provide an improved valve structure for bailers.
Another major object is to provide a valve assembly that is not defeated by particulate matter that may be present in the liquid fluid collected by the bailer.
These and other important objects, features, and advantages of the invention will become apparent as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.